In the processing of wafers into semiconductors, particularly integrated circuits, numerous steps must typically be performed and the wafers must often be transported facility to facility and internally within a facility. In recent years, semiconductor wafers have increased in size to 300 mm and more in diameter. Due to their large size, the wafers are more susceptible than ever to damage. Moreover, the density of circuits on such wafers has dramatically increased. As a result, such wafers are significantly more expensive and protecting same from contamination or breaking in transportation and processing is critical.
Specialized containers have been developed for transporting wafers. One type of container includes a separate open cassette that is received in an outer enclosure, such as the device disclosed in U.S. Pat. No. 5,782,362, hereby fully incorporated herein by reference. In this configuration, the wafers are typically received edgewise in a vertical orientation in the cassette. The cassette is, in turn, enclosed in the outer enclosure which typically includes a lower base portion and a separate upper cover or door. Another type of container, known as a horizontal wafer container, generally includes an enclosure portion with one open side. Horizontal wafer shelves are defined in the container walls, and a door is sealably finable in the open side. An example of a horizontal wafer container is disclosed in U.S. Pat. No. 6,644,477, hereby fully incorporated herein by reference. Although such containers are designed to reduce the effects of physical shock, which can damage the thin, brittle wafers, wafer containers are needed with improved shock-reducing properties.